I ran into the same problem with regards to email. All other references I've
found say the problem is because of the file size of the .pst or .ost files.
But my file sizes seemed OK - none were near the (previously in my former
Outlook2K) 2MB size. And I understood before upgrading that file sizes can
now go to 20gig or something like that. The only way I've been able to get
around it for now is I've moved and saved all my previous .pst files (I don't
have any .ost files), then allowed Outlook2007 to recreate one to at least
capture my incoming emails (I had to force through a bunch of errors/close
old archive files that would no longer open, etc.). OF COURSE ALL MY
PREVIOUS SETTINGS ETC. ARE NOW GONE. But at least I'm operating for the time
being hoping that someone can come up with a proper solution. I've also
advised my VirusScanner supplier asking for any help they might be able to
give, if anything they've done could be causing, etc. No reply yet.


"Jon" wrote:

I have Outlook 2007 which was upgraded from 2003. My Outlook 2007 runs
on a Citrix Terminal Server on Windows 2003 Enterprise Service Pack 1.
I access the Terminal Server from a Wyse thin client. My Outlook 2007
uses MAPI to communicate with Exchange 2003 Enterprise Edition. I have
no other account types configured.

During the course of the day Outlook decides to flake out and render
the error "The Messaging interface has returned an unknown error."
This occurs when trying to view any of the 14 other person's calendars
I have been granted access too. I am trying to access these calendars
from the "People's Calendars" pane.

Closing and re-opening Outlook seems to resolve access for an
undetermined amount of time. I'm not fully able to reproduce the error
at will but I have noticed it most frequently when going on 15 minute
break or 1 hour lunch.

I'm not using cached mode or PST's of any kind. My mailbox is not
terribly bloated - about 457 MB's per Exchange System Manager.

I have reviewed Event Viewer on both the Terminal Server and Exchange
Server and can find no evidence of why I get blocked.

I have tried some of the Outlook command line switches and eventually
just created a new Outlook profile. None of these eliminate the
problem.

Does anyone know of a solution to this?
___________________________________________
Remove dots before at to reply direct - Jon